@article{NUMA_1986__48_133084,
     author = {Owe Axelsson and Gunhild Lindskog},
     title = {On the {Rate} of {Convergence} of the {Preconditioned} {Conjugate} {Gradient} {Method.}},
     journal = {Numerische Mathematik},
     pages = {499--524},
     publisher = {mathdoc},
     volume = {48},
     year = {1986},
     zbl = {0564.65017},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1986__48_133084/}
}